“John Kelly will be leaving at the end of the year, we will be announcing who will be taking John’s place, it might be on an interim basis, I’ll be announcing that over the next day or two,” Trump said of Kelly, the former Homeland Security secretary.

Ayers, Vice President Mike Pence’s chief of staff, was considered to be a shoo-in for the position, but he announced he’s leaving the administration at the end of the year instead.

“I am in the process of interviewing some really great people for the position of White House Chief of Staff,” Trump said in a Dec. 9 tweet. “Fake News has been saying with certainty it was Nick Ayers, a spectacular person who will always be with our [Make America Great Again] agenda. I will be making a decision soon!”

The new White House chief of staff will enter the Trump administration at a pivotal moment, faced with the challenges of securing the president’s re-election and fending off inquiries once Democrats gain control of the House next year.